Electric compensator



p 9, 1942. L. BATCHELDER 2,297,668

ELECTRIC COMPENSATOR Original Filed 001;. 12, 1939 RETAFDA'HON LINES "TT- INV ENT OR.

ATTORNEY Patented Sept. 29, 1942 2,297,668 ELECTRIC COMPENSATOR LaurenceBatchelder, Cambridge, Mass., assignor to Submarine Signal Company,Boston, Mass., a corporation of Maine Refiled for abandoned applicationSerial No. .7

299,180, October 12, 1939. This application December 5, 1940, Serial No.368,655

2 Claims.

The present application is a division of my copending application SerialNo. 299,180, filed October 12, 1939, now abandoned.

The present invention relates to electric compensators particularly tosuch as are used for the determination of the direction of submarinesound sources. For this purpose a plurality of electroacoustictransducers for producing eleclrical response upon excitation bycompressional waves are mounted at spaced position in a predeterminedconfiguration. A wave impulse arriving from a distant source will,therefore, strike the several transducers or receivers at differentinstants of time whereby the electrical currents or voltages produced bythe said devices will var in time phase depending upon the angle whichthe direction of the sound source makes with the surface upon which thereceivers are mounted. By progressively varying the phases of theseveral electric impulses so produced in such o. manner as to bring themall into phase, the direction of the sound source can be determined bynoting the amount of phase variation required. For this purposeadjustableelectrical retardation lines are commonly employed. The outputenergy of the retardation lines may be connected to an indicating devicesuch as a pair of telephone receivers so that either a binaural or amaximum efiect is obtained when the compensator is adjusted to bring allthe received impulses into the same phase.

It is usually desirable to be able to use a compensator with either themaximum or the binaural method at will. Moreover, when using the maximummethod, it is often desirable to insert a high-pass filter in thecircuit since a sharper bearing can frequently be obtained by listeningto high frequencies only. In order to provide a simple arrangement forswitching the compensator from maximum to binaural, with or without thefilter and to equalize the energy in the telephones in the three cases,I provide a method selector switch and accompanying circuits as shownschematically in the accompanying drawing.

'The switch itself may be a five-pole, threeposition unit whose controlbar is indicated at I. The five poles or movable contacts of the switchare numbered 2 to 6. Each of these makes contact with a set of therestationary studs, A to C for the three switch positions. In position Athe telephones are connected to the retardation lines for the maximummethod with a filter inserted between the telephones and the retardationlines. In position B the connections are for the maximum method withoutthe filter but with an attenuator in the circuit. Position C is for thebinaural method with an attenuator. The filter is schematicallyindicated at l and left and rightattenuators at 8 and 9 respectively.The retardation lines are indicated at Ill, only the three outputterminals being shown. It will be understood that compensation iseffected in groups, the energy from the left group of sound receiversappearing between the terminals [3 and I5 and that from the right groupof sound receivers appearing between the terminals l4 and IS Thetelephone receivers are shown at H and I2.

With the switch' in position A as shown, the telephones are connectedfor operation by the maximum method. The outputs of both ends of theretardation lines are therefore connected together and through thefilter to the parallel connected telephone receivers. To this end theloft output terminal l3 of the retardation lines is connected throughthe brush 4 and its contact A by the lead IE to the input terminal ll ofthe filter l. The right output terminal ll of the retardation lineslikewise, through contact 2 and its stud A. is connected to the inputlead I l of the filter. The common terminal l5 of the retardation linesis connected by the lead l8 to the common side of the filter input andto the junction 19 of the two telephones II and I2. The output lead 20from the filter'is connected to the studs A of the two movable contacts5 and 6 which are connected respectively to the remaining terminals ofthe telephones l2 and II.

In position B of the switch in which the movable contacts 2 and 6 areconnected to the center studs numbered B, the filter is eliminated fromthe circuit. If this were done directly, there would be a great increasein the energy actuating the telephone receivers since the filtereliminates considerable amount. In order t- 'reduce the energy in such amanner that the volume of the output ofthe telephones will be the samewhether the filter is in or out of the 7 circuit, the attenuators 8 and9 are provided.

The attenuators 8 and 9 are chosen of such value that they will producesubstantially the same volume reduction as that produced by the filterI. For the binaural method one of these is connected in each of thetelephone circuits while for the maximum method without filter, they areused in parallel.

Thus, in position B the left terminal l3 of the retardation lines willbe connected, through the switch numbered 4 and its contact stud B,

- lead I! and the contact 4 to connect the outputs oi the two parts ofthe retardation lines in parallel so that maximum rather than binauralresponse is obtained in the telephones.

For the blnaural method the switches move to position 0, in which caseno filter is used, but the output-oi each side oi the retardation linesis separately connected to one of the telephones through one of theattenuators. The circuit is as follows: The left terminal I! through themovable contact 4 and its third position stud is connected by the lead2| to the input of the attenuator 9 and by the output lead 22 and switchmember 8 to the left telephone II. The right terminal 14 of theretardation lines is, on the other hand, connected through contact 2 andits-third position stud to the input lead 23 of attenuator 8 and by thelead 24 to the contact 5 and thence to the right telephone II.

By means of this arrangement the operator canreadily switch frombinaural method to maximum method and for the latter cut the filterin 1. In a system for determining the direction 0! a source ofcompressional waves with the aid of a plurality of spaced receivers andan electric compensator having retardation lines, the combinationtherewith of a filter, attenuation means, a pair of telephones andswitching means for selectively connecting said telephones to saidcompensator through said attenuation means for binaural listening andfor successively switching said telephones for listening by the maximummethod with attenuation means without a filter and with a filter withoutattenuation means.

2. In a system for determining the direction of a source ofcompressional waves with the aid of a plurality of spaced receivers andan electric compensator having retardation lines, the combinationtherewith of a pair of telephones, a filter, attenuation means andswitching means including means for switching said system from a maximummethod with a filter successively to the maximum method with attenuationand the binaural method with attenuation.

LAURENCE BATCHELDER.

